Influenza viruses cause annual epidemics of acute disease and periodic pandemics of serious disease. The cause epidemics acute periodic pandemics toll in morbidity and mortality from influenza ranks among the most toll in morbidity and mortality from influenza ranks among the most severe of any infectious disease during a normal year (10-50,000 deaths in the US, 250-500,000 world-wide) and can be catastrophic in a pandemic year (500,000 deaths in the US, 20-40 million world-wide during the 1918 pandemic). Annual vaccination has proven to be the most effective means of preventing influenza disease. The logistics for manufacturing influenza vaccine are organized to produce an annual supply specific for viruses expected to be circulating that year and sufficient to immunize populations most at risk. This capacity is relatively inflexible because vaccine is produced from virus propagated in embryonated hen's eggs, the supply of which must be planned well in advance. This decades-old technology can now be replaced by virus growth in cell culture, a technology that has more rigorous manufacturing standards and is more readily expandable if additional vaccine is required, as in the case of a pandemic. The goal of this project is to pursue the development of an influenza vaccine produced by a process utilizing a proprietary MDCK-derived cell line (BV5F1) created for this purpose. The specific aims of the project are to: 1. Adapt the BV5F1 cell line to serum-free/protein-free media and optimize cell growth on microcarrier beads. 2. Optimize influenza virus growth in cell culture by creating and testing seed stocks and by adjusting culture conditions. 3. Modify the downstream process for vaccine production, develop analytical techniques, and conduct pro-clinical testing of vaccine formulations. 4. Scale up, characterize, and carry out GMP production of BVSFl-derived influenza vaccine forclinical testing. 5. Conduct clinical evaluation of candidate monovalent pandemic and trivalent inactivated split vaccines in humans. [unreadable] [unreadable] [unreadable]